Cross-linked carboxymethylcellulose in combination with an alcohol soluble poly (2-hydroxyethyl methacrylate) (p-HEMA) and a permeation enhancer, such as a mixture of linoleic acid and propylene glycol, forms a hydrogel capable of delivering therapeutic levels of biologically active materials through mammalian membranes.
Transdermal drug delivery is the diffusion of a therapeutic agent into and through the skin of a mammal. It is an alternative route of administration to oral delivery of various drugs. Advantages of this type of delivery system over oral administration include lack of gastrointestinal problems, reduction of drug metabolism due to initial bypass of the liver, and the ability to continually deliver a systemic amount of a drug over a controlled period of time.
U.S. Pat. No. 4,563,182 to Stoy, V. A. and Stoy, G. B., issued Jan. 7, 1986 discloses a method of treating hemorrhoids using a rectal insert which contains a frozen hydrogel; U.S. Pat. No. 4,452,892 to Rosevear, A., issued June 5, 1984 discloses the use of a hydrogel system containing various immobilized biologically active species; U.S. Pat. No. 4,423,099 to Mueller, K. F. and Heiber, S. J., issued Dec. 27, 1983 discloses a non-uniform water insoluble interpenetrating polymer blend composition useful for the controlled delivery of active ingredients such as fragrances and bio-affecting agents; U.S. Pat. No. 4,359,483 to Kaetsu, I. and Yoshida, M., issued Nov. 16, 1982 discloses a multi-layered slow release composite; U.S. Pat. No. 4,226,848 issued Oct. 7, 1986 and its divisional U.S. Pat. No. 4,250,163 issued Feb. 10, 1981, to Nagai, T., et al disclose a pharmaceutical preparation which adheres to the mucosa of the oral or nasal cavity. The aforementioned disclosures describe various polymeric materials used as inert carriers for active substances and which in some cases are controllably released from these carriers. However, they differ from the present invention in that they do not describe the combination of cross-linked carboxymethylcellulose with an alcohol soluble poly (2-hydroxyethyl methacrylate) (p-HEMA) and a permeation enhancer, such as a mixture of linoleic acid and propylene glycol to form a hydrogel capable of delivering therapeutic levels of biologically active materials through mammalian membranes.